Power semiconductors are conventionally surrounded by plastics, that is to say organic potting compounds, to protect them against environmental influences on the one hand and to insulate them electrically on the other hand. To this end, the plastics are partly enriched with fillers that are to fulfill certain functions—for example potting compounds are enriched with fillers for adjusting a specific thermal-expansion behaviour.
Despite the enrichment of the organic potting compounds with fillers having a good thermal conductivity, the increase in thermal conductivity that is achieved in the potting compound is disappointing.
For this reason, heat dissipation of the semiconductor is predominantly attempted via the so-called thermal stack, that is to say via a good thermally-conducting connection of the power conductor to a substrate and via its good thermal connection to a base plate or a heatsink.
The electric insulation capability of the thermal stack is ensured in some case via ceramic support layers in the substrate or in other cases via special electrically insulating organic heat-conducting films.
A disadvantage of this construction, and the procedure for manufacturing power modules constructed in this way, is now that on account of the great variety of the materials needed for this purpose, attention has to be paid to their different interactions among each other, e.g. chemical or also thermo-mechanical interactions. Since on account of these interactions it is often also necessary to carry out certain process steps separate from each other, or one after the other, this produces a high outlay in terms of work and also time.